This invention is related generally to dispensing apparatus and, more particularly, to apparatus for dispensing flexible sheet material including apparatus for dispensing from plural sources of material.
Dispensers for flexible sheet material, such as paper toweling and the like, are well known in the art. These dispensers typically discharge the sheet material from one or more rolled webs stored within the dispenser. The material is dispensed when the user grasps the material tail, which extends outwardly from the dispenser, and pulls the tail away from the dispenser.
The web of sheet material is typically drawn from a roll on which the material is wound through a nip formed by a drive and a tension roller and then out of the dispenser. The rotational force imparted to the drive roller by the moving web material may be used to operate a cutting mechanism which completely or partially cuts the web into sheets of predetermined length. Examples of cutting mechanisms powered at least in part by the moving web material include U.S. Pat. Nos. 5,441,189 (Formon et al.), 4,621,755 (Granger), 4,122,738 (Granger) and 4,404,880 (DeLucca). In each of these patents, the cutting blade is powered to extend from the drive roller to cut the web. Of course, other types of web cutting devices, such as the stationary blade shown in U.S. Pat. No. 5,526,973 (Boone et al.), have also been used in prior dispensers.
An important issue affecting these types of dispensers involves the need to provide the dispenser with sufficient sheet material so that the dispenser can be used for extended time periods without the need for service by an attendant. One solution to this problem has been to provide the dispenser with plural sources of material, typically in the form of rolled material webs, These dispensers include a primary roll of web material which is initially dispensed and further include one or more secondary web rolls which are dispensed once the primary roll has been depleted.
A variety of transfer mechanisms have been developed in an effort to transfer the secondary roll web material to the nip once the primary roll web has been depleted. However, these mechanisms have certain disadvantages. For example, U.S. Pat. Nos. 4,010,909 (Bastian), 4,165,138 (Hedge), 4,317,547 (Graham, Jr. et al.), 4,358,169 (Filipowicz et al.), 4,403,748 (Cornell) and 4,756,485 (Bastian et al.) utilize one or more rollers mounted on complex articulated frames to urge the secondary roll material into the nip. Such arrangements are disadvantageous because the large number of moving parts required by these devices unduly adds to the cost of manufacture and assembly and increases the likelihood that the dispenser may fail during operation. These devices are further disadvantageous because they rely on complex and potentially unreliable apparatus to determine that the primary roll has been depleted.
By way of further example, U.S. Pat. Nos. 4,611,768 (Voss et al.), 4,807,824 (Gains et al.) and 5,400,982 (Collins) utilize a finger-like xe2x80x9ctucking devicexe2x80x9d to urge the secondary roll material into the nip. Again, complex apparatus are required to make many of these devices operational. Moreover, the tucking device remains in contact with the secondary roll web material after the transfer and can place unnecessary drag and frictional forces against that web material potentially resulting in tearing of the web material.
It would be a significant improvement in the art to provide dispenser apparatus with an improved transfer mechanism that would reliably transfer web material from a secondary roll to the nip upon sensing that the primary roll material has been depleted and which would include an elegant design requiring fewer parts resulting in lower costs of manufacture and increased reliability of operation.
It is an object of this invention to provide an improved dispensing apparatus and material transfer mechanism overcoming some of the problems and shortcomings of the prior art.
Another object of this invention is to provide an improved dispensing apparatus and material transfer mechanism which provides a reliable transfer of secondary material to the nip upon depletion of the primary web material.
Yet another object of this invention is to provide an improved dispensing apparatus and material transfer mechanism which requires fewer parts than prior art material transfer mechanisms.
Still another object of this invention is to provide an improved dispensing apparatus and material transfer mechanism which has an improved design versus prior art material transfer mechanisms.
Yet another object of the invention is to provide an improved dispensing apparatus and material transfer mechanism which has a rugged design yet is economical to manufacture and assemble.
It is also an object of this invention to provide an improved dispensing apparatus and material transfer mechanism which directly senses the amount of primary material remaining to be dispensed.
An additional object of this invention is to provide an improved dispensing apparatus and material transfer mechanism which minimizes wear on the material to be dispensed.
These and other objects of the invention will be apparent from the following descriptions and from the drawings.
The invention is directed to improved apparatus for dispensing flexible web material from primary and secondary rolls including an improved transfer mechanism for reliably and simply transferring the secondary roll web to the web feed apparatus once the transfer apparatus senses that the primary roll web has been depleted to a predetermined extent. The invention represents a significant advance over prior art products because of its elegant design. The invention requires fewer parts than prior art devices. The few parts that are required are simpler, require fewer moving parts and are easier to manufacture and assemble. The device minimizes the chance for material breakage or damage. All of these design advances contribute to a less expensive, more reliable dispenser apparatus.
The apparatus includes a frame for rotatably supporting drive and tension rollers and drive and tension rollers mounted thereon. The drive and tension rollers extend across substantially the width of the web. A nip is formed at the junction of the drive and tension rollers. Web material is fed from a roll stored with respect to the dispenser, through the nip and out of the dispenser through a discharge opening. Cutter apparatus for cutting the web material into separate sheets of predetermined length is preferably included.
In broad terms, the improved transfer apparatus comprises a one-piece transfer arm, first and second transfer rollers rotatably secured with respect to the transfer arm and a sensing member secured with respect to the transfer arm in position to contact the primary roll web surface. The sensing member permits movement of the transfer arm and transfer rollers to the transfer position once the primary roll diameter diminishes to a predetermined extent.
The transfer arm is mounted for movement with respect to the frame between a ready position and a transfer position and is biased toward the transfer position. The first and second transfer rollers are configured and designed to extend only partially across the tension and drive rollers respectively. In the ready position, the first and second transfer rollers are preferably spaced apart from the drive and tension rollers. In the transfer position, the first and second transfer rollers engage an edge portion of the secondary roll web and urge such edge portion against the tension and drive rollers respectively causing the secondary roll web to be drawn into the nip for dispensing from the apparatus. The sensing member preferably rides directly against the outer surface of the primary roll web and permits movement of the transfer arm toward the transfer position as the primary roll web diminishes in diameter.
The preferred transfer arm comprises a one-piece component with first and second ends. The transfer rollers are mounted along the first end and the sensing member is mounted along the second end. The transfer arm is preferably designed with an upper section including the first end and a and lower section including the second end. The upper and lower sections of the transfer arm meet to form an obtuse angle. It is highly preferred that the transfer arm is mounted for pivotal movement at a single transfer arm pivot axis. This advantageous arrangement permits the transfer rollers to be easily moved toward the respective drive and tension rollers as the transfer mechanism moves to the transfer position.
In highly preferred embodiments, the transfer rollers are secured to a transfer roller arm. The transfer roller arm is movably secured along the transfer arm first end. The transfer rollers are configured and designed to contact only one edge of the secondary roll web. It has been found that a transfer roller width (also referred to herein as an axial length) of approximately 15 mm is highly desirable.
It is highly preferred for the inventive transfer mechanism to include biasing apparatus for urging the sensing member directly against the primary roll outer edge. The biasing apparatus maintains direct contact between the sensing member and the primary roll web surface ensuring reliable movement of the transfer apparatus to the transfer position. A spring is a suitable form of biasing apparatus for use with the invention.
The invention""s compact design and use of a single transfer arm with transfer rollers which extend only partially across the drive and tension rollers dispenses with any need for bulky structures which span the entire width of the dispenser and which require multiple articulated frames to support such structures. The smooth surfaces of the preferred transfer rollers minimize wear on the material to be dispensed.